Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Results of Operations
Gross revenues									$ 1,097,738	$ 1,207,510	$ 1,316,466
Less: Inter-segment revenues	$ 293,087	$ 245,645	$ 282,911	$ 269,910	$ 291,836	$ 251,237	$ 312,655	$ 341,781	1,091,553	1,197,509	1,311,917
Revenues	293,087	245,645	282,911	269,910	291,836	251,237	312,655	341,781	1,091,553	1,197,509	1,311,917
Gross profit	21,451	14,891	26,703	28,891	23,127	(2,614)	28,212	32,278	91,936	81,003	125,991
Operating income (loss)	(17,112)	$ (5,862)	$ 5,174	$ 7,321	3,531	$ (21,210)	$ 8,237	$ 14,301	(10,479)	4,859	40,882
Segment assets	558,033				586,030				558,033	586,030	564,967
Capital expenditures									8,711	11,908	13,939
Depreciation and amortization									20,347	21,602	21,441
Electrical Infrastructure [Member]
Results of Operations
Gross revenues									255,931	373,384	349,011
Less: Inter-segment revenues									255,931	373,384	349,011
Revenues									255,931	373,384	349,011
Gross profit									18,300	7,137	29,301
Operating income (loss)									(16,531)	(8,309)	11,144
Segment assets	161,207				183,351				161,207	183,351	135,298
Capital expenditures									493	1,390	1,611
Depreciation and amortization									4,359	5,198	5,008
Oil Gas & Chemical [Member]
Results of Operations
Gross revenues									324,546	247,423	252,973
Less: Inter-segment revenues									322,772	240,523	249,795
Revenues									322,772	240,523	249,795
Gross profit									33,423	12,675	18,553
Operating income (loss)									8,798	(8,783)	(3,503)
Segment assets	111,064				129,177				111,064	129,177	91,350
Capital expenditures									1,514	829	1,481
Depreciation and amortization									5,904	6,299	4,811
Storage Solutions [Member]
Results of Operations
Gross revenues									319,106	483,254	564,738
Less: Inter-segment revenues									314,696	481,696	563,512
Revenues									314,696	481,696	563,512
Gross profit									25,778	55,651	67,843
Operating income (loss)									(5,907)	22,928	33,449
Segment assets	149,695				166,742				149,695	166,742	201,875
Capital expenditures									3,346	2,017	3,882
Depreciation and amortization									6,623	7,277	8,124
Industrial [Member]
Results of Operations
Gross revenues									198,155	103,449	149,744
Less: Inter-segment revenues									198,154	101,906	149,599
Revenues									198,154	101,906	149,599
Gross profit									14,435	5,540	10,294
Operating income (loss)									3,161	(977)	(208)
Segment assets	58,816				53,754				58,816	53,754	67,569
Capital expenditures									0	38	104
Depreciation and amortization									3,461	2,828	3,498
Unallocated Corporate [Member]
Results of Operations
Segment assets	$ 77,251				$ 53,006				77,251	53,006	68,875
Capital expenditures									3,358	7,634	6,861
Intersegment Eliminations [Member]
Results of Operations
Less: Inter-segment revenues									6,185	10,001	4,549
Revenues									6,185	10,001	4,549
Intersegment Eliminations [Member] | Electrical Infrastructure [Member]
Results of Operations
Less: Inter-segment revenues									0	0	0
Revenues									0	0	0
Intersegment Eliminations [Member] | Oil Gas & Chemical [Member]
Results of Operations
Less: Inter-segment revenues									1,774	6,900	3,178
Revenues									1,774	6,900	3,178
Intersegment Eliminations [Member] | Storage Solutions [Member]
Results of Operations
Less: Inter-segment revenues									4,410	1,558	1,226
Revenues									4,410	1,558	1,226
Intersegment Eliminations [Member] | Industrial [Member]
Results of Operations
Less: Inter-segment revenues									1	1,543	145
Revenues									$ 1	$ 1,543	$ 145